“8 MILE,” the movie opening today starring rapper Eminem, is a series of curiosities stacked high: Can Eminem act? Why is acclaimed director Curtis Hanson helming this roman à clef? Why is “8 Mile” being touted as a serious movie?

Let’s start with Eminem. It would seem that history is against him. When top 40 stars take to the cineplex, the results are normally disastrous: Mariah Carey, Vanilla Ice, Cyndi Lauper, Mick Jagger, Madonna, Britney Spears, the Spice Girls. (If this list seems female-heavy, that’s because it is. My pet theory on why female singers want to be movie stars is simple: job security. Hollywood may be tough on older women, but it’s nowhere near as merciless as the pop charts. Men can still be rock stars in their 30s and 40s. Women can’t. I suspect this gender difference explains why Madonna–the most career-savvy performer since Paganini–has been trying to establish herself as a screen presence since she was in her late 20s.)